The hand-held device having a photographing function is very popular in recent years. Due to the development of the semiconductor technology and the mighty advance of the optical design technology, the size of the optical element is getting smaller and smaller. Therefore, the digital camera lens can be widely applied to the mobile device, e.g. the cellphone, hand-held game console, MP3 player, notebook computer, tablet PC, global positioning system, event data recorder, etc.
Since the pixels of the photosensitive element of the digital camera lens are getting higher and higher, the request for the imaging quality of the digital camera is also getting higher and higher. Currently, the protective lens for the mobile device having a photographing function in the market is usually made of a transparent acrylic material or other transparent macromolecular materials. The protective lens made by these materials provides the basic protection for the digital camera lens, and enables the digital camera lens to be normally imaged without being damaged. However, when the digital camera is used by the user for a period of time, the surface of the protective lens made by the acrylic material or the transparent macromolecular material will be damaged due to the frequent friction or collision. At this time, if the digital camera lens takes images via the damaged surface of the protective lens, the imaging quality will be poor, or the photosensitive element cannot correctly and effectively determine the imaging of the object to be taken, which results in the output of the noise. This causes the function of the digital camera to be lowered or inactive.
Please refer to FIGS. 1(a) and 1(b). FIG. 1(a) shows the front of a conventional image capturing device 10, and FIG. 1(b) shows the back of the conventional image capturing device 10 of FIG. 1(a). As shown in FIG. 1(a), the conventional image capturing device 10 includes a front housing 101, a liquid crystal display 102 and keys 103. As shown in FIG. 1(b), the conventional image capturing device 10 further includes a protective lens 104 and a back housing 105.
Please refer to FIG. 2, which shows a conventional image capturing device structure 12. The conventional image capturing device structure 12 includes a protective lens 104, a back housing 105 and a lens module 106. The protective lens 104 is disposed on the back housing 105 for protecting the lens module 106 thereunder. The protecting lens 104 is mainly made of a macromolecular material, which includes the acrylics or polycarbonate resin.
Please refer to FIG. 3, which is a cross-sectional view of the conventional image capturing device structure 12 of FIG. 2. As shown in FIG. 3, the image capturing device structure 12 further includes a liquid crystal display 102 and a circuit board 107. The lens module 106 is electrically connected to the circuit board 107. The circuit board 107 is disposed under the back housing 105. The back housing 105 surrounds the lens module 106. The lens module 106 is disposed under the protecting lens 104 so that it can be protected by the protecting lens 104.
In FIG. 3, the tempered glass also can serve as the protecting lens 104 for the lens module 106. Although the tempered glass is harder than the macromolecular material, the user might be scraped by the tempered glass due to frequent use. Besides, if the image capturing device 10 is fallen onto a hard surface (e.g. the ground) by accident, the tempered glass would be cracked due to the collision of external force. The cracked surface has a sharp angle so that the user is easily cut thereby. Therefore, using the temped glass to serve as the protecting lens 104 for the lens module 106 has potential danger.
Another prior art is to use the stack of multi-layers of materials to serve as the protecting lens 104. However, such stack will result in the loss of light, the poor imaging and the generation of noise.
Please refer to FIG. 4, which is a cross-sectional view of another conventional image capturing device structure 14 in the Taiwan Patent No. M267775. The image capturing device structure 14 includes a protecting lens with multi-layers of materials 109, a back housing 105, a lens module 106, a circuit board 107 and a liquid crystal display 102. The protecting lens with multi-layers of materials 109 includes a protecting lens 104 and a protecting layer 108. Although the protecting layer 108 can enhance the protecting ability of the protecting lens with multi-layers of materials 109, the transmittance will be greatly reduced, thereby affecting the imaging quality of the lens module 106.
In order to overcome the drawbacks in the prior art, an image capturing device is provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.